The present invention relates to a control cable length self-adjusting device which is applicable, in particular, to the adjustment of the length of sheathed control cables used, in general, in industry and in the automobile industry in particular.
As is well known, said control cables are formed, basically, by a steel cable having a sleeve or sheath appropriate for the anticipated service conditions. They are used as a linking member between control means and devices of any nature. In automobiles, the control cables are used, among other cases and just as one example of application, as a linking member between the accelerator pedal and the corresponding engine carburetor mechanism. The control cables, further to the sheathed steel cable as such, regularly comprise at the ends thereof respective connection terminals, the shape of which depends on the needs of each particular application and, suitably arranged relative to one of the ends of the sheathed steel cable portion, a self-adjusting device for the length of said sheathed cable portion.
The purpose of the self-adjusting device is to compensate, for each vehicle in particular, the tolerance required by the sheathed cable portion of the control cable, with regard to the length thereof, to achieve an adequate transmission of the forces and movements. The sheathed cable portion length is adjusted, as described hereinafter, after the control cable has been suitably attached at both ends to the control means (which may be a lever, a pedal or a control arm) and to the controlled device (which may be an automobile carburetor, a lock or any other remote controlled mechanism), respectively, and after the self-adjusting device has been anchored to a fixed point on the vehicle structure.
Generally speaking, the known self-adjusting devices comprise a base body having means for the anchorage thereof to the vehicle structure, a regulating rod firmly attached at one of the ends thereof to the corresponding end of the control cable sheath and through which the steel cable may slide an adjusting spring which initially is supplied compressed to a pre-set value; and manually operated regulating rod retaining means.
The length of the sheathed cable portion is adjusted, in general, by the self-adjusting devices. With the control cable mounted in the vehicle and the control means and controlled device in the pre-set service conditions, the regulating rod is first freed by hand from the self-adjusting device retaining means; therefore the rod, urged by the regulating spring, moves to an adjusted position in which the resilient reaction of the sheathed cable portion when placed under compression balances the reaction of the regulating spring, at which time the sheathed cable portion length is adjusted. Secondly, while retaining the pre-set service conditions of the control means and controlled device, the adjusted position attained by the regulating rod is set, also by hand, by operating once again the self-adjusting device retaining means.
As an example of known self-adjusting devices, there may be cited the device disclosed in Spanish patent P 9001269 comprising the members described above, further to those which characterize it. The device according to Spanish patent P 9001269 has manual retaining means operating means formed by a shaft having a transverse extension allowing the user to perform the release and/or retaining operations for the regulating rod during the sheathed cable portion length adjusting operations.
The known self-adjusting devices, such as those described in the foregoing paragraphs, suffer in general from the drawback of being formed by a large number of components, making the production costs thereof higher. Another drawback of such known embodiments is that, to adjust the sheathed cable portion length, the user must manually operate the retaining means acting on the regulating rod to release it and/or retain it, which makes the assembly costs of the self-adjusting device in the vehicle more expensive.